Field-magnet structure



No Model.) 2 Sheets-Sheet 1. D. P. THOMSON 8v H. GEISENHNER.

FIELD MAGNET STRUCTURE.

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. P. THOMSON 8v H. GEISENHNER.

FIELD MAGNET STRUCTURE.

UNITED STATES PATENT OFFICE.

YORK, ASSIGNORS TO YORK.

TIIE GENERAL ELECTRIC COMPANY, OF NE\V FIELD-MAGNET STRUCTURE.

SPECIFICATION forming part of Letters Patent No. 571,462, dated November 1'?, 1896.

Application filed August 18,1896. Serial No. 603,150. (No model.)

To ctZZ whom t may connerie:

Be it known that we, DAVID P. THOMSON and HENRY GEISENHNEE, citizens of the United States, residing at Schenectady, in the county of Schenectady, State of New York, have invented certain new and useful Improvements in Field-Magnet Structures, (Oase No. 388,) of which the following is a specification.

Our invention relates to the field-magnets of dynamo-electric machines, and particularly to those in which the field-magnet revolves and the armature remains stationary. Most of the examples of this type of machine are of the alternating-current type, in which it is necessary for efficiency to employ a laminated field-magnet structure. At the same time the pole-tips for the best effect should be expanded, so that (among other reasons) the magnetic density need not be forced unusually high in the air-gap by reason of the smallness of the pole-face through which the lines are projected. The pole-tip itself should also be laminated. With this construction it has been found difficult to devise sufficient means for rendering the field-magnet coils removable. It has been proposed to have a cast inner structure, to which the laminated fieldmagnet poles might be bolted in various ways; but this is for some reasons objectionable, occasioning a dissimilarity in the material in the magnetic circuit which is undesirable and rendering the connecting means between the pole and the central structure difficult of access. Solid poles secured in the same way have also been used, but this is objectionable for the same and other reasons.

The construction which we have devised consists in a laminated held-magnet structure with salient poles having laminated pole-tips, the tips of the poles being removable, so that the eldqnagnet coil may be placed in position. To effect a secure junction and to reduce the reluctance of the magnetic circuit to the lowest point, we arrange the lamina; of the pole-tip with interlocking projections and i also have projections upon the lamina; forming the body of the pole. Insulated bolts clamp the laminze together, the surfaces of the laminze also having a frictional engagement tending to assist the strength of the bolts and render the structure exceedingly solid and compact and capable, when revolved at high speed, of resisting centrifugal and magnetic stresses.

It is manifest that the general type of our invention thus described may be much varied. Ve may, if so desired, intersperse the individual laminze of the tip, having projections between the laminze of the pole itself, or we may arrange the pole-tip with a number of projecting laminae in a group. The form and location of the projecting parts which make the connection between the pole-tip and the body of the pole may a-lso be indefinitely Yaried.

The accompanying drawings show some of the forms which our invention may assume.

Figure l is a side elevation, partly in section and partly broken away, of a field-niagnet embracing our construction. Fig. 2 is a partial section upon the line 2 2 of Eig. l. Eig. 3 is a side elevation of a single poletip of modified form. Fig. 4; is a section on the line i i of Fig. 3. Eig. 5 is a plan, and Fig. 6 a side elevation, of another modification. Figs. 7 and S are similar views of still another modification. j Figs. 9 and l0 are side elevations of field-magnets assembled according to our invention, Fig. 9 showing a spider with a rim and Fig. l0 a spider in which the arms are connected only by the laminze.

In Fig. 1, A is the body of the field-magnet. B B are the pole-tips. The laminas forming the body of the field-magnet have projecting portions G, adapted to form interlocking surfaces with the laminze of the pole-tip. In dotted lines at G' we show how the laminae of the field-magnet structure may be reversed in po* sition, so that with a single die the effect of two locking projections upon each polar end maybe produced. By reversing the position of the individual laminas of the pole-tips I5 a similar effect maybe produced. F is a iield magnet coil, one of which, of course, would be provided for each of the salient poles. Bolts E are used to lock the lamina in place after the pole-tip has been placed over the Iield-l magnet coil, and similar bolts E E are elnployed to assemble the pole-tip before it is put in place.

In Fig. 2 the same construction is shown,

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only one of the bolts being illustrated, and the interleaving of the lamin forming interlocking surfaces is illustrated.

In Figs. 3 and et a modified form is shown. Some of the laminze of the pole-tip are of the size shown in full lines. Some of them are cut aWay, as shown in dotted lines, to correspond to the projecting' ends of the poles. Similarly, some of the laminre of the poles are as shown in full lines and others have their ends projecting into a pole-tip, as shown in dotted lines. Preferably the laminze alternate in position in groups, and this subdivision or alternation may be carried as far as is desirable. As before, bolts E E lock Ithe pole-tip in place.

In Figs. 5 and G We show another modified construction. In this case undercut or dovetailed projections are formed upon the polar projection, and the pole-tip B is secured in place by keys I I. rIhis is not, however, the preferred form oi our invention.

In Figs. 7 and S We show still another modiiication, in Which the ends B B' of the poletip are formed with dovetailed projections and the ends of the pole itself are formed with undercut grooves corresponding in form to the interlocking portions of the polar tips IS I3.

In Fig. D a spider II with a rim is shown, having the laminze connected to it by dovetailed projections and having the polar tips of our invention.

Fig. l0 corresponds to Fig. 9, except that the spider is rimless, the arms being disconnected, so that the structure may move slightly under changes of temperature.

That We claim as new, and desire to secure by Letters Patent of the United States, is-

1. A 'field-magnet structure for a dynamoelectric machine, consisting of salient poles oi' laminated structure, provided with separate laminated tips, and means 'for securing the tips to the poles.

2. A field-magnet structure for a dynamoelectric machine, comprising laminated salient poles provided with laminated expanded tips, some of the laminae of the tip provided with' tenons which register with suitable spaces in the lamina; of the pole, and means for holding the parts in engagement.

A iield-magnet structure for a dynamoelectric machine, comprising laminated polepieces provided with laminated expanded tips or pole-faces, the laminze of the pole and tip having engaging tenons and spaces, and arranged in groups, with means for sccurin g the parts together, thus maintaining them in place by the strength of the securing means and by their frictional engagement.

In Witness whereof We have hereunto set our hands this I-ith day of August, 1806.

DAVID F. TIIOMSQN. HENRY GEISENIIONER.

TWitnesses:

I3. B. HULL, GnNnvInvn ILIYNES. 

